Quasi-steady-state melting mode during combined laser irradiation of semiconductor materials

The concentration of heat sources created by the absorption of laser radiation striking a substance in the vicinity of a melting front, and their advancement along with the front, are investigated. A simple analytical solution to Stefan's problem for this laser irradiation mode is found. The temperature field distributions are obtained and expressions are derived for the rate of melting front movement during combined exposure to laser pulses with nanosecond, microsecond and millisecond durations. Although the analysis does not contradict experimental findings elsewhere, the theory cannot be compared quantitatively with those experiments inasmuch as the latter are qualitative in nature.